Separation of tall oil components



R. M. CHRlSTENSON ET AL SEPARATION OF TALL OIL COMPONENTS Filed Sept. 4, 1948 Nov. 6, 19.51

Patented Nov. 6, 1Q51 ,SPARTI'ON ,OETALL QIICOIYIPONENTS? Roger M. Christensen and Ralph E. Harpt, Mil- `ivt'fauk'ea'Vi/isa. assignors to. Pittsburgh Plate; t z Glass; (lompany,;.=Allegheny County, Ba., a...cor

p orationofPennsylvania y p' Apli'cationfjS-eptember 4, 194s', serialsNoA-frsani Thev present invention rel-ate'seta processestoff fractionating tall oilfin order toseparategtherosn acids from vthefatty acids'thereof andit has=par= ticular relation to'vtheefractionation of tall oillbyv4 liquidphase extraction of themethyl .esters of talloil fatty acidsefrom'eth'e'-soapsl'oflrosin acid/sc' by means`=of A an appropriate Y`soli/"ent system.

An' object of-theinventi'o'niis to provide a proc ess of the foregoingtyp'efin 'which thesfatty acid esters canbev rapidly-and-fs'rnoothly extracted from the aqueous alcoholsirosiniacid soap-solution by continuousfcountercurrentfcontact in any appropriate column. t l l s p A second object of the invention is to provide a process of the foregoing type which is simple and economicallandieiicientl in operation .l

A- third Objectis i'logprovide-aJ -process of' the" foregoing type -Wherebyfihardfrosin--freeof fatti/iacids may be obtained from'tall oil.

A fourth' objecttofprovide aprocess of -the* foregoingA type whereby"fattyfacidsfor fattyacidiE esters free of rosin' acidslmayrbei obtained fromf tall'oil. f 'f1 f' w.

These land f other objects of the inventionwill be apparent from consideration of'fthefllovmingff 254 specification and-'the appended claims:y

Tall oil is a well known icy-'product offth'eJKraft Paper Industry. It-comprisesa highlyrcomplex-I mixture Y of rosin acids,- polymers offrosinf acids;-`

fatty acids; sterols-and other constituents. Heref Y 30:L

cheap, low-gradeimater-ials; About `allthat-hasr 35.5.

been accomplished has -beento 4subject`v the mixe ture to distillationlwherebyftofobtain-a fraction; considerably enrichedv in 'fatty acids,V a.; second:Y fraction enriched in rosinacids and", in* some cases, a distillation residue containing some40 rosin acids and fattyY acids-anda high concentration of sterols; rosin polymers-andthe likesl Obviously the fractionationsVv Were neverl sharpaV andclean-cut. A' Y Y Itv has also been proposedv tofobtai'n aLw more 45 complete separation of fthe rosin Aa'cidsand fatty4 acids into portionsofi higher commercial value' by" subjecting the tall oil 'to an Iesterication .'re'- f action with lower alcohol such as/methanol; ast

atresult of which operationVthe'fatty'acids aref/ 50.

selectively*y converted to fattyfacidesters: The rosin acids couldv then bef selectively` neutralized! withalkalisuch as sodium hydroxide- In-suchl mixture the fatty acid-esters and -unsaponiiiableLl isi-claims," (o1. 2cd-msm l 2..V Y soapsf-by the. application ofy benzene. 'Ihisdatteii'fV type of process lhas heretoforefremained Vofscnnei theoretical Value especially foranalyticalfpurffposesein. the laboratory-but ithas neverrjasfefar as is known, enjoyedganyiv substantial degree-of. commercial success. This lack ofsuccess was apparently largelyduewto" thefact that the rosin acid: soaps and ;the esters. of :fattyaacidsftendedlto form emulsionslwithzthe benzengtoisuch;degree: that itwas-prac-tcally impossiblecta effecttsatis: factory-separation, in a continuous countercure-'irentv system. The.y present invention involves;` thediscoveryiAvr that;V by"y proper adjustment.: of theavariousf com.-:- p onentstof the, mixtures =of;solyents and :the prod-fr ucts of vesterification,andrneutralization:of talliohl,r mixtures could be obtained which'would undergtrY readyv and relatively-completesseparationl whena. the mixtures were sub-j lectedfato. extraction Withffaf, solventsuch as naphtha in countercurrent' dem: inzanrappropriate column;z

For, az.r betteri understanding;v of the: inventic'nny reference may/ be: madefto: the, accompanying; drawing. inr-Which ;the;single f'gure diagrammatiw cally illustrates@J simple formsof apparatus suit-f' able .for use in thepracticemf7 .the-,inventionz Tall oilit is to.be.:recognized',l.will vary..firr.conn-:f`

position: dependentV upon: the: sources, and; theer method of operation by which it is obtainedz) Inc general, the composition will bevapproximately as follows:

f Percent Fatty.4v acids;y 3531*,0550: Rosin .acids` 35;.to1r551 Unsaponiable-.matteri 6; tof.`v 12E Iii accordancewith tle provisions ofthe pres` ent invention' a compound suchV as. above d-lscribed is. subjected to. treatment' by` the. following stages.l

' II ESTERFICATION'* matter could" b'eextracted from therosinaci'd-' .desir-ed;.theialcoholiwhioh is in excess-:of that rees is.' .y1 *L 31- qui'red for estericati'on could also be evaporated. The following constitutes an appropriate example of a suitable esterication mixture:

Parts by weight Liqro .or crude tall oil 165.8 Methanol V Y Y 39 Commercialsulfuric acid 1 5.5

The sulfuric acid, of course, is a mere catalyst and. more or less might be employed as will beV understood by those skilled in the art. Preferably it will be within a rangeof about'two to 10 parts by Weight.

The reaction is effected by ture in a suitable aparatus. Rei'luxing is continued s long as methyl alcohol continues to` combine and water of esterifcation. is given off..

Usually the reaction will be complete within a period of three hours or less but maybe con A II.V N EU'IRALIZATION #The above esteried mixture in an appropriate reaction vessel is mixed with 45 parts by weight of. Water (preferably soft) and caustic to neutralize the vsulfuric acid is added. In the particular mixture, 4.67 lbs. of caustic, e. g. caustic soda, is suflcient. The causticized mixture may bebriefly agitated. Methanol is next added in order tomake up an aqueous methanol solution. In .the specific example contemplated herein, methanol comprised 98.13 parts by Weight. Alkali (caustic soda) in an amount to neutralize the rosin acids was next added. In these specific examples, the alkali vconstituted 8.3 parts by weight and it was dissolved-in 27.22 parts by Weightzoiwater. .The alkaline solution was added slowly..until .the mixture; wassiightly on the alkaline.. side.. In this specific instance, the pH value Was 10.4. .It will .be apparent that the rosin acidsinthe .nalmixtureare present as their s soaps,l thesulfuric acid is present as a sodiumsalt and the fatty-.acidsare present as the methyl.esters.

The soapsoluti'oh :In-.order to prepare aqueous alcohol solutions suitableforextraction with naphtha to separate fatty acid esters fromthesoaps of rosin acids in accordance With theprovisions ofthe present invention, the solids including the soaps of rosin acids," esters of fatty acids, sodiumsulfate and other constituents all designated herein as solids are made up in solution in Water and methyl alcohol to form a mixture which when intimately contacted by shaking or by counter-current extraction vin a column Will separate into sharp, clean-cut phases at once. In practically all instances the components of the mixture will fall within the range: 7 to 60% of methanol, 15 to 70% Water, 20. to 65% solids made up of fatty acid esters, rosin acid soaps, solids, etc. The preferredv mixture will comprise 10 to 40% methyl alcohol, to 50% water and 25 to 62% solids.

In a speciiic example a solution was made up upon the basis of starting materials 42.09% tall oil, 34.8% methanol, 18.40% water, 3.30% sodium hydroxideV and 1.41% sulfuric acid. This mixture could lbe flowed in intimate Vc ountercurrent contact with naphtha in .a suitable column later ,to

refluxing the Ymix- -Y 4 be described to obtain rapid and thorough extraction of the fatty acid esters and to obtain quick and eilicient phase separation.

In a further example a mixture was made up comprising 60% solids, 12% methanol and 28% Water. This mixture was extracted at 130 F. with naphtha having a distillation'range of about 90? C. to 115 C. and beingcompose'd of essentially heptanes and octanes.

` The mixture Would readily separate from the naphtha in the column. This mixture is of especial" value for use in the practice of the in- Vention since thevpercentage of solids is high andthe requirements of methanol are low.

These mixtures are particularly applicable to the use of naphtha and notably of naphtha approximating a heptane grade to extract the fatty acid esters frein'th soap-ester solution. This y point illustrated by the fact that a system comprising 34.8% methanol, 18.4% water, 3.3% sodium ,hyrdroxide, 1.41% sulfuric acid, 42.1% tall oil solids when shaken with benzene did not separate into layers even after standing for a period of 24 hours. Howeverg when the same mixture was shaken. with naphtha of heptane grade complete separation, occurred within one minute and but little or nonaphtha remained in .the `resin-soap layer.v Although naphtha of hexaneheptane or octane range boiling at to C. is preferable the use brother liquidl parainic petroleum naphthas is contemplated such as C3 to C12 hydrocarbons.

Extraction of the esters from the soap-esterY Vsolution A mixture so Aconstituted vis vWell adapted for extraction with hydrocarbon such as Ypetroleum naphtha and preferably ,of `the heptane range by countercurrent operations. Preferably, the column employed for .therextracton will be relativlylong, forexample 40 ft.Y or more. There would appear to lbe no Yupper limit to the height of the column other than those imposed by the economics of vconstruction and operation. In actual operations a column of 49 it. packed with Berl saddles has operated very satisfactorily. The soap-methyl estersolution should be fed into the top or near the top of the column and the naphtha into the `column rnear the base. The ratio 0f naphtha to soap-methyl esterr solution may be approximately 90 parts by volume to 70 partsy by volume. Certainyariations in the ratio of soap solution ofl methyl estersand naphtha are contemplated. For example, the naphtha may be as low as GOfparts by volume or as high as 400 partsby -volume to 1,00. parts by volume of the solution. .The column lpreferably is operated ata temperature within arrange of 80 to 135 F. The rate of feed of the soap-methyl ester solution and naphtha should be.V adjusted so that adequately complete separationof the phases can occur while the mixture isin the column. Of course, excessiveratesof feedwill result in ilooding. That is, excessive amounts of the soap soluton will be' carried backward bythe naphtha or the naphtha will fail to rise satisfactorily and will be carried out in the soapsolution.` VThere should,be no .fiow of the phasesin streams or channelscthrough each other but asuniform com- .,mingling without yemulsification as is possible.

These conditions c axrreadily `be observed bythe operator by examination of the products from the columns. Upon the basis of a cylindrical column of2 in. diameter, a feed o f 70, Cc., of the soapmethyleestermixture #n.80 cc... Qf.. naphtha per ite "is satisfactory. fBy"apiirpriarte increase can be vattained.

It will be appreciated that the methyl esters are taken up by the naphtha. Also a small amount of the soaps of rosin acids are carried over into the naphtha. For complete recovery of "the soaps it may be desirable to wash the methyl ester-naphtha solution with water in a second column which may be similar to the first. In'such Washing operation the amount of water employed will vary, dependent upon-the degree of `completeness of the removal Vof. the'soaps desired. Equal volumes of Waterand-naphtha-'solution of methyl esters usually will be suiicient. The Wash column may be operated -at atem perature of 80 to 150 F. Under-these conditions` emulsification is avoided.

The washed naphtha solution of methyl estersv may then be subjected to a number of Adifferent treatments. The naphtha, for example, may be evaporated to obtain an ester mixture havingthe following characteristics: f

mixture may then be distilled over vacuum to yield a yellow methyl ester fraction' and a pot residue. Inv the s'pecic example the distillate' constituted 60.0% and the pot residue constituted 39% of the methyl ester fraction which in turn represented a yield of 52% from the original tall oil. The'methyl ester distillate had -a free fatty acid content of .69%. It Wil-l be-appa're'nt that the methyl esters could also vbe subjected to saponication or hydrolysis to obtain the free fatty acids which could then be distilled as such. lso the esters, after distillation, may be subjected to such hydrolysis to obtain the free fatty acids. These acids may be employed for various purposes such as the production of resins, the production of -soaps and similar purposes.

There will remain a distillation residue or pitch very rich in unsaponifiable matter that can be workedup by the technique disclosed in application VSerial No. 7015900, by Roger M. Christenson and Stewart W. Gloyer entitled Separation of Unsaponiable Matter fromv Tall Oil Residues and filed October 8, 1946 and made a part-hereof tovlrecover sitosterol and the like. v Y

' he 'solution of rosin :soaps in queous alcohol passing vfrom the bottom of the Virst Icolufrnnrnay be subjected to acidification, e. g. with'strong mineral acid such as H2SO4 or HCl to recover the free rosin acids which may be washed with water in order to remove salts and alcoholand'then stripped of solvent thereby producing a hardv dark rosin of approximately the following properties: Acid value .1163 Rosin acid value 1 'l '166 Unsaponiable 1;0

reaction, tall oil, fatty acids are esteri'ed with methyl alcohol in the presence .of a strong minof the column diameter, ahyde'siredfeedf-rate eral: acid fsutzli a'ssulfuricacid -inaccordafrlce l'w-iti conventional esterication technique. The 'mixtureisconductedby linef6 to neutralizer'9'where the mixture isfdiluted andthe rosin acids are reacted With valkali (e. g. lNaOI-I) to form rosin acidsoaps. rhe apparatus further comprises la column I0` of any convenient material packed appropriately with Berl-saddles or other packing material. A soap solution of methyl esters-water, alcoholand rosin soaps made 'up as previously described fed into the column as indicated at I I. 'Naphtha for extracting out the methyl esters from the soap solution is fed into the column I0 asindicated atjI2. The alcohol solution of rosin acid soaps passes out ator near the bottom of the column as indicated at I3, while the solution of methyl esters of fatty acids dissolved in naphthapasses out as indicated at I4. The naphtha solution may be fedto a second column I5 near the bottom thereof for washing with Water. Water is fed into the column I5 near the to'p thereof at I6 at an appropriate rate. The water in which is dissolved the residual'soaps in the esterenaphtha solution is drawn off as indicated at I'1 at the bottom of the column. The naphtha solution of esters essentially free from soaps, but still containing the unsaponiflable matter passes off at'the top of the column through conduit I8 and is passed for appropriate treatment. For example, it may pass to still I9 where the naphtha is evaporated and recovered for re-use as indicated at 20. The esters may then be discharged at I9a to a pot still 2l for distillation. The residue from the pot still comprising nearly all of the unsaponiable matter in the ester frac tion may be drawn off as indicated at 22. The treatment of this pot residue does not constitute a particular feature of the present invention. However, it will be Vapparent that it may be subjected to various treatments to recover the various 'componentsssuch as the vsterols or the fatty acid resters contained therein.

` The rosin acid' soaps in aqueous methyl alcohol drawnY offas indicated at I3 and II are passed to acidier 23 where mineral acid (H2SO4) or the like) is added at 24. Upon acidification, the mixture separates into two layers and the top rosin acid and naphtha layer passes out at 26 to still 2 for removal of naphtha or other volatile matter. If desired, the naphtha solution may be water washed prior to distillation for the removal of traces of mineral acid. Hard 4rosins are takenfrom thestill. The bottom alcohol, salts and water layer passes through line 2S to still 529 for recovery ofV alcohol. A water solution of salts lpasses out as a residue at 39. The alco# hols pass out at 3 I.

"It will also be apparent that the `methyl esters from column I5 may be treated with alkali such as sodium hydroxide or sodium carbonate to form soaps of the fatty acids and the soapsfrom which the unsaponiable matter including the sterols 'of tall oil can be extracted with naphtha. Subsequently, the fatty acids can be regenerated by acidification. A For example, the esters and unsaponiable matter from still I9 may be refluxed with sodium hydroxide in an amount of molecular equivalency of the ester content or an excess, e. g. excess. The resultant solution may be adjusted Vby addition of Awater and an alcohol to such concentrations that the solution can be'extracted countercurrently with naphtha in a proportion of l'to 2'0 volumes ofnaphtha per volume of soap solution. The unsap'oniable material agrees? will be taken out in large measure by the naphtharand'the fatty acids canbe recovered by acidification of the soap solution with *sulfuric acid, hydrochloric acid or the like. The amount of acidl should be molar or approximately molar with respect to the total available sodium in the` mixture." This can be determined by adding acid until the solution becomes neutral or slightly acid. The acids can then be distilled.

- A highly important feature of the invention resides in the applicability of and the application of countercurrent technique in the contacting of the soap-ester solutions with naphtha in column l0. By the employment of the principles of the invention, it is quite feasible to effect such countercurrent extraction of the mixture of esters of tall oil fatty acids, rosin acid soaps and unsaponiable matter in water and methyl alcohol with'naphtha without any tendency to emulsify. Satisfactory separations of phases are therefore obtained at comparatively rapid rates of flow. By application of countercurrent technique of contacting the solutions, highly satisfactory removal of the unsaponiable matter and methyl esters from the rosin acids is obtained even by use of very low volumes of naphtha.

In order to demonstrate the economies cf countercurrent technique as compared with batchwise extractions, a number of experimental runs were conducted. A solution of tall oil fatty acid esters, rosin acid soaps and unsaponiable matter cf tall oil in Water and methanol and comprising: 34.8 methanol, 1.41% sulfuric acid; 18.4 Water, 3.3% sodium hydroxide; 42.1 tall oil solids (as sodium sulfate) was prepared.

Extractions were conducted as hereinafter described. The rosin acid soaps were then exhaustively extracted with naphtha of heptane grade and the percentage of unsaponiable matter and methyl esters thus taken out was determined.

One portion of the solution was .extracted batchwise with naphtha of heptane average molecular weight in a proportion of volumes in a single application. The resultant rosin soap solution was found still to contain 1.85 percent of unsaponiable matter and methyl esters.

In a second batchwise extraction, equal volumes of naphtha of heptane grade and soaps of rosin acids were contacted. The resultant rosin acid soap solution contained 5.19 percent of unsaponifiable matter and methyl esters.

In a third batchwise extraction, a rosin acid soap solution of the above constituency Wasextracted with naphtha in two separate operations. The volume of naphtha in each instance being equal to the volume of the soap solutions. The resultant rosin acid soap solution as obtained contained 1.86 percent of unsaponiable matter and methyl esters.

In a fourth batchwise extraction, the rosin acid soap solution was contacted with naphtha in a batchwise operation with three volumes of naphtha divided into three equal portions. The resultant rosin acid soap solution contained 1.31 percent of unsaponiable matter and methyl esters.

In contradistinction in a countercurrent operation, the solution of tall oil, fatty acid esters, rosin acid soaps and unsaponiflable matter of the foregoingV constituency was contacted countercurrently in the column I0 with naphtha in a proportion of 1.25 volumes of naphtha per volume of the solution. The resultant rosin acid soap solution containedrLZ percent of unsaponifiable matter and methyl'esters.

The Vresults of these runs are tabulated as follows: Y Y

' From these examples it will be apparent that a single countercurrent extraction is more eiective than three applications by batch technique using V*two and one-half times as much naphtha.

Obviously the`V countercurrent technique admits of the use of much smaller apparatus and requires much less application of heat in the distillation of the naphtha from the recovered fractions.

VIf desired the techniques as previously described herein may also be applied to the fractionation of the mixed fatty acids and rosin acid materialV obtained from the distillation of tall oil. For example, if crude tall oil is fractionately distilled, the first main fraction consisting mostly of fatty acids and a second fraction consisting largely of rosin acids are obtained. This second fraction contains enough fatty acids and unsaponiable matter to give it properties undesirable for most applications. It is either a very viscous material or a partially crystallized mass and is not comparable to hard, brittle Wood rosin. By the application ofthe technique described for the fractionation of tall oil and constituting a part of this invention, it is possible to separate the fatty acids and unsaponiable matter from the rosin ccncentrate constituting the second fraction to yield a hard, brittle rosin.

In a specific example, tall oil was subjected to distillation in accordance With conventional technique to obtain a first fraction having a high content of fatty acids and a low content of rosin acids. There Was also obtained a second fraction comprising as its major component rosin-acids admixed with some fatty acids and unsaponifiable matter. In the specific example the rosin acids constituted 60% of this second fraction.

In order to separate the fatty acids and unsaponiable matter from this second fraction, it was subjected to an esterication operation by reuxing 30 parts of the distilled fraction with 16.5 parts of methanol and 1 part of concentrated sulfuric acid. The parts as herein given are by Weight. The mixture Was cooled to room temperature and diluted with 8.3 parts of methanol. The resultant solution Was then further treated With 3 partsof sodium hydroxide dissolved in 6.9 parts of soft Waterto convert the free rosin acids into sodium salts VWithout splitting the fatty acid methanol esters. The techniques of esteriiication and neutralization have already been described.

VThe resultant solution of fatty acid methyl esters, rosin acid soaps and unsaponifable matter, When made up to the desired concentration as previously described, could be extracted countercurrently with parainic hydrocarbons to separate the methyl esters of fatty acids and unsaponiflable matter. To this end, the fatty acid methyl esters and unsaponifable matter were extracted from the rosin soaps in the solution by contacting the neutral? 'mi-xtuie- 'with mixed 'heptanes andoctanes; 'Thenaphtha extract soluti'on was water .wasl'ied t'olremovelen-trained rosin acidlsoapsandthelnaphtha was evaporated tof recover the fatty acid methyl yesters and unsaponifl-able matter. y

Thewa-sh water containingjtracesof rosin soap from the washing of the combined naphtha extracts; was added 'to the extracted soap solution and the total mixture wasL acidified with acids, e. g. mineral acids such' as diluted'sulfuric acid. TheV rosin layer `which was' separated' was water washedY andi evaporated to. yield al hard rosin Which'was brittle, .of Fvv grade and' having, an acid value of' 172.4' andI which had a ball and ring softening` point of'Y 168 After -briey heating the rosin to 300" C. and cooling the product'. of K .color grade, 170.1.` acid. value and 169 F'. ball and ring softening point,v was obtained. This fraction was clear and" brittle. y'The yield of rosin was 61.3% basedupon the lstarting material. It was a high grade rosin with-very little. plasticizi-'ng acids'. Y

The mixture of fatty acid methyl -esters and un' saponiable `matter obtainediby extraction of the solution of esters, soaps and unsaponifiable matter with naphtha constituted. 40.31% basedvv upon the starting material. It. had-'af 4GardnerV color of 9.5 and was essentially yfree-of rosin acids;

The fatty acid esters could easily. be hydrolyzed to obtain the free acids by treating them in accordance with conventional technique, e. g. Twitchellizing, high pressure splitting or saponification followed by acidification.

Although the present invention is described with reference to certain embodiments thereof, it will be apparent to those skilled in the art that it is not so limited but that various modifications can be made therein without departure from the spirit of the invention or the scope of the appended claims.

We claim:

1. In a process of fractionating tall oil to separate the rosin acids from the fatty acids, the steps which comprise esterifyingthe fatty acids with lower aliphatic alcohol, diluting of the mixture with water, neutralizing the rosin acids with sodium hydroxide, making up 1 volume of the resultant mixture of rosin acid soaps and fatty acid esters into a solution containing 25 to 62% solids, '7 to 60% of a lower alcohol and 15 to 70% water, and countercurrently contacting the resultant solution with 1 to 20 volumes of naphtha by continuously introducing the solution into an upper portion of a vertically elongated extraction zone and continuously introducing the naphtha into a lower portion of the same zone and drawing off a naphtha solution of esterified fatty acids above the point of introduction of the solution and drawing off a solution of water and lower aliphatic alcohol containing rthe rosin acid soaps below the point of introduction of 'the naphtha.

2. The steps as defined in claim 1 in which the naphtha is of heptane grade.

3. The steps as defined in claim 1 in which the V alcohol is methyl.

4. A process of separating the rosin acids and fatty acids of tall oil, whichprocess comprises esterifying .the fatty acids with methanol, diluting the mixture with water, neutralizing the acid components of the mixture with vcaustic soda and makingup the resultant mixture of fatty acid esters and rosin acid soaps with water and methyl tadrift,soo

lo alcohol in the proportion of 28% water-and 12% 'methyl alcohol and 60% solids and countercurrently4 extracting Vthe resultant solution with naphtha'of heptane grade at a temperature within a range vof 80 to 135 F. by continuously in'- troducing the solution into an upper portion of a vertically elongated extraction zone and continuously introducing the naphtha into-a lower portion ofth'e samezone and drawing off a naphtha solution ofY esteried fatty acids above the point of introduction of the solution and draw ing off' a solution of water and lower aliphatic alcoliciv containing the rosin acid soaps below the pointof introduction of thenaphtha.

In a process of fractionatin'g tall oil to'separate the rosin acidn from thev fatty acid, thefsteps which: comprise le'sixeri'fy'ing the fatty acidsA with methyl alcohol, diluting the mixture withf water, neutraliaing the rosin acidslwit-h sodiurnhydroxl ide, making up the resultant mixture of. rosin acid soaps and fatty acid -e'stersasa solutioirin a mixture of water and" methyl alcohol, the mixture comprising 'l to 60% by weight-of methyl alcohol, fto 70% by weight of water and 20jto 65'%1bywei`glit of solids comprising theifatt'y acid estersland rosin acid soaps, then intimately con@- tacting the resultant mixture in counter-current flow with naphtha at a temperature of about 80 to 135"F.', by continuously introducing the solu- 1 tion intov an upper portionV of a verticallyelonfgated extraf'ztionY zone and continuously introiducin'g: the naphtha in desired proportiony in't'o a lower portion of thesamezoneand' drawing' loff a naphtha solution of esterified fatty acids above the point of introduction of the solution and drawing off a solution of water and lower aliphatic alcohol containing the rosin acid soaps below the point of introduction of the naphtha, separating the naphtha as a separate phase and evaporating off the naphtha to obtain the fatty acid esters. V 6. The steps as defined in claim 5 in which the naphtha is of heptane grade.

7. In a process of fractionating tall oil to separate the rosin acids from the fatty acids, the steps which comprise esterifying the fatty acids with methyl alcohol, diluting the mixture with water, neutralizing the rosin acids with sodium hydroxide, making up the resultant mixture of rosin acid soaps and fatty acid esters as a solution in water and methyl alcohol, the mixture containing 10 to 40% methyl alcohol, 15 to 50% water and 25 to 62% solids, then intimately countercurrently contacting the resultant solution with naphtha at a temperature of about to F. by continuously introducing the solution into an upper portion of a vertically elongated extraction zone and continuously introducing naphtha into a lower portion of the same zone and drawing off a naphtha solution of esterified fatty acids above the point of introduction of the solution and drawing off a solution of water and lower aliphatic alcohol containing the rosin acid soaps below the point of introduction of the naphtha in order to extract out the fatty acid esters in the naphtha and evaporating off the naphtha to obtain the esters.

8. The steps as .defined in claim '7 where the naphtha is of heptane grade.

9. A process as defined in claim 7 in which the naphtha is employed in a range of 60 to 400 parts by volume per 100 parts by volume of the solu tion.

10. In a process of fractionating tall oil to l-l fatty acids and av third of which is essentially unsaponifable matter of tall oil, the steps which comprise selectively esterifying the vfatty acids of the tall oil with methyl alcohol, diluting the mixture with water, neutralizing the rosin acids Vremaining with sodium hydroxide, making up the resultant mixture of rosin acids soaps, fatty acid `esters and unsaponifiable matter as a solution in Water and methyl alcohol, the mixture containing to 40% methyl alcohol, 15 to 50% water and to 62% tall oil solids, then intimately countercurrently, contacting the resultant solution with naphtha at a temperature of about to F. by continuously introducing the solution into an upper portion ofA a vertically elongated extraction zone and continuously introducing naphtha into a lower portion of the same lzone and drawing off a naphtha; solution of ,esteried fatty acids abovethe point of introduction of the solution and drawing oia solution of water and lower aliphatic alcohol containing the-rosin acid soaps below the point of 12. Aprocess as dened in claim 10 in which the fatty acids recovered are further distilled in order to obtain substantially pure fatty acids.

13. In a process of separating the fatty acids from the rosin acids and unsaponiables of tall oil, the steps of (I) making up a mixture comprising upon the basis of starting materials (a) 42% tall oil in the form of a product obtained by esterifying the fatty acids therein with methanol and with H2SO4 as a catalyst, and neutralizing the rosin acids and sulfuricV acid (b) 35% methanol l(c) 18% water (d) the rest being alkali and sulfuric acid combined as salts and alkali combined as rosin acid soaps, then (II) countercurrently vextracting the resultant solution with paralnic naphtha averaging about 7 carbon atoms per molecule at a temperature of 80 to F. i

ROGER M. CHRISTENSON. RALPH E. HARPT. Y

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,736,802 Schultze Nov. 26, 1929 2,348,970 Gayer et al May 16, 1944 2,348,971 Gayer et al May 16, 1944 2,423,232 Freeman 1 July 1, 1947 

1. IN A PROCESS OF FRACTIONATING TALL OIL TO SEPARATE THE ROSIN ACIDS FROM THE FATTY ACIDS, THE STEPS WHICH COMPRISE ESTERIFYING THE FATTY ACIDS WITH LOWER ALIPHATIC ALCOHOL, DILUTING OF THE MIXTURE WITH WATER, NEUTRALIZING THE ROSIN ACIDS WITH SODIUM HYDROXIDE, MAKING UP 1 VOLUME OF THE RESULTANT MIXTURE OF ROSIN ACID SOAPS AND FATTY ACID ESTERS INTO A SOLUTION CONTAINING 25 TO 62% SOLIDS, 7 TO 60% OF A LOWER ALCOHOL AND 15 TO 70% WATER, AND COUNTERCURRENTLY CONTACTING THE RESULTANT SOLUTION WITH 1 TO 20 VOLUMES OF NAPHTHA BY CONTINUOUSLY INTRODUCING THE SOLUTION INTO AN UPPER PORTION OF A VERTICALLY ELONGATED EXTRACTION ZONE AND CONTINUOUSLY INTRODUCING THE NAPHTHA INTO A LOWER PORTION OF THE SAME ZONE AND DRAWING OFF A NAPHTHA SOLUTION OF ESTERIFIED FATTY ACIDS ABOVE THE POINT OF INTRODUCTION OF THE SOLUTION AND DRAWING OFF A SOLUTION OF WATER AND LOWER ALIPHATIC ALCOHOL CONTAINING THE ROSIN ACID SOAPS BELOW THE POINT OF INTRODUCTION OF THE NAPHTHA. 